Semi-active vibration control of an 8x8 armored wheeled platform

This study proposes skyhook and fuzzy logic based semi-active control strategies to isolate sprung mass motions of 8x8 military vehicle and provide ride quality, road holding and firing accuracy for a platform, removing the passivity constraints of semi-active suspension system. The governing differential equations of motion of 8x8 platform for semi-active vibration control are formulated analytically and validated under multi body dynamics environment. Sprung mass acceleration and displacement are measured on a quarter car set up experimentally to assess the efficacy of skyhook and fuzzy logic controllers. Control strategies, viz. continuous skyhook control, cascade loop control and cascade loop with ride control are implemented. Cascade loop with ride control is employed such that the outer loop stabilizes heave, pitch and roll motions of full vehicle whereas the inner loop, through fuzzy controller, isolates vehicle from uneven disturbances. Various parametric studies are also performed with 8x8 semi-active suspension systems in terms of stochastic road inputs to represent cross country terrain profile. Furthermore, effect of proposed strategies on ride comfort, road holding, amplitude and settling time of vehicle body motions after firing large projectile from gun and aiming accuracy of the fire control system are investigated. It is demonstrated that cascade loop with ride control in semi-active mode improves vehicle ride comfort and road holding and accuracy of fire control system and rate of fire of gun.